4.5
Greywater is man-made
– an untapped water
and nutrient resource
Greywater
(shower, washing,
cleaning, etc.)
constructed
wetland, gardening,
wastewater pond, biol.
treatment, membranetechnology
irrigation,
groundwater
recharge or
direct reuse
Challenges and possibilities
Greywater represents environmental challenges:
-
Unpleasant odours
Health hazard (pathogens and toxic compounds)
Soil erosion
Pollution of surface water and groundwater
Mosquito breeding
Benefits of using treated greywater and sludge:
+ Reduces water shortage
+ Reduces environmental degradation, eutrophication
and health hazards
+ Reclaims otherwise wasted nutrients
+ Alleviates food shortages and poverty
+ Protects the quality of groundwater
Courtesy of Nicola Rodda University of KwaZulu Natal, Durban
Urban horizontal water and nutrient flows
Urban
waste
Surface &
ground water
Rain
Storm
water
Urban
Compost
Faeces Compost &
hygienization
Lower
quality
Treatment
Drinking
water
Sludge
Solid
waste
Activities
Horticulture
Agriculture
Urine
Hygienization
& concentration
Forestry
Grey
water
Hygienization
membrane
biological
Aquaculture
Black
water
Wetland
aquacult
Industry
Waste
water
Sludge
fractionation
biological
treatment
Household
Jan-Olof Drangert, Linköping University, Sweden
Urban unintended vertical flows of contamination
Landfill
Sludge
bed
Irrigation
Pit
latrines
Septic
tank
Petrol
station
Sewers
Soil layer with organic material, clays and charged particles
Groundwater (saturated aquifer)
Jan-Olof Drangert, Linköping University, Sweden
The effects of urbanisation on groundwater
utilisation, quantity and quality
Water volumes
(supply & disposal)
Imported
water
time
Shallow wells
Periurban
wells
Deeper
wells
Settlement
size
Effect on
quantity: None Falling grw-level Over extraction Excess infiltration
Effect on
quality:
None
Growing pollution
Excessive pollution
Courtesy of G. Jacks, Royal Institute of Technology, Stockholm
All groundwater under cities is polluted
Source: Powell
et al., 2003
Wastewater = clean water + what has been added
Component
Content in different fractions
Faeces
Impact
(potential)
Means of control
- water scarcity
- heat loss
- investment
- water logging
- behaviour
- fee structure
- water saving
equipment
- ‘no’ faeces in water
- hygienic handling
- aerobic treatment
- minimize exposure
Physical, aerobic,
anaerobic treatment
Urine
Greywater
4-10
(WC)
0
(no flush)
20-40
(WC)
0
(no flush)
80-200
Pathogens
(bacteria,
viruses,
helminths)
high
very low
low
- infections
Organic matter
BOD kg/p/year
5.5
2
Excreta 7.5
10
Phosphorus
kg/person/year
0.2
-deplete oxygen
-bacteria growth
-eutrophication
Nitrogen
kg/person/year
0.5
Water
lit/person/day
flush included
0.4
4
Mean value 5.0
0.05-0.3
0.5
urine separation,
precipitation, etc
urine separation,
aerobic/anaerobic
Heavy metals
present
negligible
present
-eutrophication
-consume oxygen
-toxic to humans
Organic toxic
compounds
negligible
negligible
present
-toxic to humans
Aerobic treatment
Pharmaceutical
residue/hormone
present
negligible
negligible
-toxic for aquatic
Degrade in top soil
use other products
Courtesy of Peter Ridderstolpe, WRS, Uppsala, Sweden
What do we put into the water?
What is in soap, detergents, shampoos, solvents, disinfectants,
paints, medicines, pharmaceuticals, etc ?
Soap contains alkali salts with long-chained fatty acids:
Hard soap usually contains sodium (Na) 
Liquid soap usually contains potassium hydroxide (K) 
Detergents can contain (check list of contents on package)
– Phosphorous  in water and  on soil
– which can be replaced by potassium  or 
– Salts: sodium  or 
– Bleaches: chlorine  and peroxide 
– Fluorescent whitening agents 
– Non-degradable substances:
zeolites  or  and fillers  or 
Courtesy of H. Jönsson, Swedish University of Agricultural Sciences, Sweden
Toxic organic compounds
O
O NH
P
NH
Ifosfamide
0% biodegradable
HO
HO
Phthalates
O
O
O NH
OH P NH
Cl
Cl
Cl
Cl
Glufosfamide (ß-D- Glc -IPM)
70% biodegradable, improved up-take in the gut
Source: Kümmerer, 2007
Metals in wastewater & excreta
Element
Copper
1.
2.
3.
4.
5.
6.
Daily
intake
(mgr)
Output in
faeces
(mgr/kg P)
Found in
sludge
(mgr/kg P)
Quotient
Output in
urine
(mgr/kg P)
Quotient
3
2
Cu
1,400
1,000
14,000
14
Chromium Cr
300
214
1,300
6
Nickel
Ni
120
88
720
8.3
16
78
Zinc
Zn
11,000
7,200
25,000
3.5
424
69
Lithium
Li
17
12
Mercury
Hg
5
40
11
Lead
Pb
23
16
1,500
94
Cadmium Cd
14
10
44
4
3,5
68
3
5
0.65
206
2,000
0.64
63
16
0.32
94
137
Courtesy of G. Lindgren, Sweden
Can we cope with the chemical society ?
What we know:
1. Metals and man-made organic
material do NOT disappear, but
30 000
chemical
compounds
”treatment”
2. ... they may adsorb to particles
3. Organics decompose into ...
4. inorganic substances and gas,
but do NOT disappear
20
monitored
29 980
unknowns
Jan-Olof Drangert, Linköping University, Sweden
A: Source control comes first
s
l
u
d
g
e
Aerobic process:
- Trickling filter
- Soil/sand filter
- Mulch filter
- Vertical flow constructed wetland
- Ponds– facultative
maturation etc.
Anaerobic process:
- Anaerobic baffled
reactor
- Anaerobic pond
Usages:
Minimise water use,
reduce contamination
by chemicals, oil,
particles, fats, excreta
Quality of material &
workmanship is a
FIRST priority!
Courtesy of Peter Ridderstolpe, WRS, Uppsala, Sweden
Storage of
urine/faeces,
septic tank,
grease filter,
screen, etc.
Service water
Resorption
Surface irrigation
Sub-soil irrigation
Infiltration
To surface water
Households can contribute – NOW!
Use as little water as possible by mimicking the use of water in
buckets (do not wash under running tap, take quick showers, mend
leaking taps, put full loads in washing machines, ...... )
Do NOT add solid matter to water (put food scraps from plates
and utensils in the waste bin, do not flush tooth picks etc. down
the toilet, do not put cigarette butts in urinal, ...... )
Do NOT add chemicals and oils to the water while using it (put
fat from frying pan in the solid waste bin, use biodegradable
soap and detergent, do not flush paint, medicines or other
chemicals down the toilet, .... )
Buy and use environmentally friendly products for your home
Then you can use greywater in your garden, and you avoid blockages
Jan-Olof Drangert, Linköping university, Sweden
Households can invest: install proper
devices in your kitchen and bathroom
When you build or retrofit your home:
- Buy water- and energy-saving devices e.g. water-efficient
shower heads, taps, washing machines and low-flush toilets
- Install a dry or low-flush urine-diverting toilet to recover
nutrients and to save water
- Avoid leaking taps and keep a record of the amount of water
used every now and then to monitor your usage
Example: A new suburb in Stockholm, Sweden with proper
saving devices achieved (www.stockholmwater.se):
- a 40 % reduction in water use
- a 25% reduction in hot water use (= energy saving)
- a 50% reduction in eutrophying substances to the lake
Jan-Olof Drangert, Linköping university, Sweden
”Benign by design” - manufacturers need not
make products with problematic content
Classical view on functionality
of chemical products:
+ stable (persistent)
New view:
+ complete and fast degradation
+ no risk of harmful effects
+ effective
+ effective
+ efficient
+ efficient
+ affordable
+ affordable
Source: Kümmerer, 2007
TPS non-biodegradable for washing powder
LAS readily biodegradable replacement of TPS
Supervision: nonylphenol in car care products
mg/kg dry
matter
400
350
300
250
Nonylphenol in digested sludge in Stockholm,
mg/kg d.m.
Nonylphenol
in digested
sludge
Henriksdal
200
150
Car wash
Bromma
Applyin
g law on
product
choice
100
50
0
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Courtesy of Arne Jamtrot,
Stockholm City
Media attention: Triclosan in toothpaste
% of toothpastes
containing triclosan
% in
2006:
% in
2010:
000
00
00
0
00
0
0
Courtesy of Arne Jamtrot, Stockholm City
Subsidies: Hg in sewers at dental clinics
3.5
Did the campaign make a difference?
3
280 kg mercury was removed 1998 and 2004
mg Hg/kg DS
2.5
2
1.5
Section of sewer with Hg nuggets
1
0.5
0
1997
1998
1999
2000
2001
2002
2003
2004
2005
Courtesy of Arne Jamtrot,
Stockholm City